Quahog (Mercenaria mercenaria)
Alternate common names: Hard-shell Clam, Cherrystone,
Color: Shell color ranges from white to grey, with dark rings.
Size: 1 to 4 inches wide.
Habitat: Burrows just below the sand intertidally and subtidally.
Seasonal appearance: All year.
Quahogs, or hard-shell clams, are shellfish that inhabit the mud flats along the eastern seaboard from Canada to Florida. They range in size from 1 to 4 inches wide, and vary in color from white to gray with dark rings.
Life History and Behavior
Populations are most concentrated in estuaries between Cape Cod and New Jersey where the salinity is lower than that of the open ocean. Quahogs do not remain fixed for life in one spot; they move through the mud using a muscular foot. With two short siphons, the quahog filters water in and out of its shell, absorbing plankton, bacteria, and oxygen. Quahogs are extremely efficient filter feeders, and large quahogs can filter about a gallon of water per hour. Through this filtering process, they can absorb pollutants, bacteria, and viruses in polluted waters. Although low levels of pollutants do not harm the clams, eating polluted quahogs can pose a risk to human health. However, if the pollution source is removed, the quahog can clean itself simply through its regular filtering action.
Common predators include sea stars, whelks, crabs, snails, birds, some fish, and humans. The entire body of the quahog is edible, not just the large adductor muscle that is also found in larger species of clams. Empty shells with a small hole the size of a pencil point are evidence of consumption by moon snails, the New England dog whelk, or oyster drills.
Adapted from The Uncommon Guide to Common Life on Narragansett Bay. Save The Bay, 1998.